<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <style type="text/css">
      html { height: 100% }
      body { height: 100%; margin: 0; padding: 0 }
      #map_canvas { height: 100% }
    </style>
    <script type="text/javascript"
      src="http://maps.googleapis.com/maps/api/js">
    </script>
    <script type="text/javascript">
	var myCenter=new google.maps.LatLng(51.508742,-0.120850);

	function initialize()
	{
	var mapProp = {
	  center:myCenter,
	  zoom:5,
	  mapTypeId:google.maps.MapTypeId.ROADMAP
	  };

	var map=new google.maps.Map(document.getElementById("map_canvas"),mapProp);

	var marker=new google.maps.Marker({
	  position:myCenter
	  });
	  
	var infowindow = new google.maps.InfoWindow({
	  content:"Hello World!"
	  });


	infowindow.open(map,marker);  

	marker.setMap(map);
	
	google.maps.event.addListener(marker, 'click', function() {
	  infowindow.open(map,marker);
	  });
	}

	google.maps.event.addDomListener(window, 'load', initialize);
	
	</script>
  </head>
  <body>
    <div id="map_canvas" style="width:100%; height:100%"></div>
  </body>
</html>